feat(kugetsu): create env directory and files during init

Update cmd_init to create:
- ~/.kugetsu/env/ directory
- ~/.kugetsu/env/default.env (template)
- ~/.kugetsu/env/pm-agent.env (template)

Users can then edit these files to add their tokens/secrets.

skills/kugetsu/scripts/kugetsu

@@ -947,6 +947,25 @@ EOF
         echo "Created config file: $KUGETSU_DIR/config"
     fi
 
+    mkdir -p "$ENV_DIR"
+    if [ ! -f "$ENV_DIR/default.env" ]; then
+        cat > "$ENV_DIR/default.env" << 'EOF'
+# Default environment variables for all agents
+# Add variables that all agents should have access to
+# Example:
+# GITEA_TOKEN=your_token_here
+EOF
+        echo "Created default env file: $ENV_DIR/default.env"
+    fi
+    if [ ! -f "$ENV_DIR/pm-agent.env" ]; then
+        cat > "$ENV_DIR/pm-agent.env" << 'EOF'
+# PM Agent environment variables
+# These override default.env for the PM agent
+# GITEA_TOKEN=your_gitea_token_here
+EOF
+        echo "Created pm-agent env file: $ENV_DIR/pm-agent.env"
+    fi
+
     local existing_base=$(get_base_session_id)
     local existing_pm=$(get_pm_agent_session_id)